In recent years, light-emitting diode (LED) is widely applied and plays an increasingly important role in various fields like display system, lighting system and automobile tail light.
FIG. 1 shows an existing vertical light-emitting diode structure, which converts the growth substrate to a conductive substrate with a mirror system via bonding technology, thus increasing luminance. In the aforesaid structure, the top-surface electrode generally shields the conductive through-holes under the light-emitting epitaxial laminated layer, so that some light cannot be emitted, and therefore influence chip luminance.
In existing technology, to avoid overlap of the top-surface electrode and the conductive through-holes under the light-emitting epitaxial laminated layer as much as possible, the top-surface electrode and the bottom ohmic contact electrode are distributed staggered by electrode alignment. For example, the Chinese patent CN103890981A discloses a light-emitting diode, wherein, the ohmic contact electrode 7 is arranged in a position not overlapped with the bonding pad 12a of the surface electrode 12, and in a middle position between linear parts of the ohmic electrode 11. This technical scheme solves the shielding problem of the top-surface electrode. However, on the one hand, it requires electrode alignment, which increases process complexity. In addition, it has high precision requirement of alignment, and any incorrect alignment is easy to cause poor yield. On the other hand, forward voltage value (VF) increases as LOP (Light Output Power) improves.